This invention relates, in general, to fabrication of optical devices and, more particularly, to optical layers and optical waveguides.
At present, optical layers and optical waveguides are made in a variety of methods such as, photolithography, diffusion, ion implantation, or a combination of any of the above. Generally, these methods for making optical layers and optical waveguides are complex, inefficient, and are generally not suitable for high volume manufacturing. However, as use of optical layers and optical waveguides increase, a need for a fabrication method and a structure that allows for an efficient and a cost effective manufacturing method of optical layers and optical waveguides will be required.
Conventionally, optical layers and optical waveguides are manufactured by a combination of photolithographic and etching processes. For example, a conventional optical layer is fabricated by applying a suitable optical material onto a substrate. A photoresist material is then applied onto the optical material and subsequently patterned by a photolithography process. The pattern defined by the photolithography process is subsequently transferred into the optical material by an etching process that removes exposed portions that are not covered by the photoresist material. The substrate with the etched pattern is subsequently cleaned, which removes the residual photoresist material and leaves a resultant optical layer in place on the substrate. As is described above, conventional fabrication of optical layers is a sequence of complicated and expensive processing steps.
Waveguides are fabricated in a similar manner by stacking the optical layers each having an appropriate index of refraction on top of each other, thus creating a sandwich structure having a core region and cladding regions surrounding the core region. Typically, these stacked optical layers are generated by the previously described combination of photolithographic and etching processes. However, several problems are generated due to the stacking of the optical layers such as alignment, sizing, and etching problems. As can be seen by the example provided above, the manufacturing of optical layers is a series of complex processes which are very expensive. Further, manufacturing of waveguides are even more complex, more expensive and more costly than the fabrication of optical layers.
It can be readily seen that conventional methods for manufacturing optical layers and waveguides have severe limitations. Also, it is evident that conventional processes that are used to fabricate optical layers and optical waveguides are not only complex and expensive but also not amenable to high volume manufacturing. Therefore, a method for making optical layers and optical waveguides is highly desirable.